Fuel injector arrangement for compressive mixture internal combustion engines

ABSTRACT

A fuel injector arrangement for compressive mixture internal combustion engines having a fuel quantity control arrangement, and with an air intake passageway within which there is located a variably actuatable throttle valve. The fuel quantity control arrangement is carried out through the intermediary of a differential pressure producer which measures the airflow rate, and which includes connected thereto a pneumatic control power amplifier.

United States Patent 1 Chattopadhayay et al.

[ Dec. 30, 1975 l FUEL INJECTOR ARRANGEMENT FOR COMPRESSIVE MIXTURE INTERNAL COMBUSTION ENGINES (75] Inventors: Asoke Chattopadhayay, Norf; Karl Schmidt, Wehl, both of Germany [73] Assignee: Deutsche Vergaser GmbH & Co.

Kommanditgesellschaft, Neuss, Germany [22] Filed: Aug. 12, 1974 [2]] Appl. No.: 497,148

[30] Foreign Application Priority Data Aug. 13, 1973 Germany 2340834 [52] U.S. Cl. 123/139 R; 261/50; 123/32 AB [51] Int. Cl. F02M 9/06 [58] Field of Search 261/50 A, 50 AA [56] References Cited UNITED STATES PATENTS Obermeycr, Jr. 261/50 A 10/1967 Soubis 261/51 11/1970 Handtmann et al. 261/51 Primary Examiner-Wendell E. Burns Assistant Examiner-James W. Cranson, Jr. Attorney, Agent, or FirmHaseltine, Lake & Waters 57 ABSTRACT A fuel injector arrangement for compressive mixture internal combustion engines having a. fuel quantity control arrangement, and with an air intake passageway within which there is located a variably actuatable throttle valve. The fuel quantity control arrangement is carried out through the intermediary of a differential pressure producer which measures the airflow rate, and which includes connected thereto a pneumatic control power amplifier.

11 Claims, 4 Drawing Figures US. Patent Dec. 30, 1975 Sheet 1 of2 3,929,114

US. Patent Dec. 30, 1975 Sheet 2 of 2 3,929,114

FUEL INJECTOR ARRANGEMENT FOR. COMPRESSIVE MIXTURE INTERNAL COMBUSTION ENGINES FIELD OF THE INVENTION The present invention relates to a fuel injector ar rangement for compressive mixture internal combustion engines having a fuel quantity control arrangement, and with an air intake passageway within which there is located a variably actuatable throttle valve.

DISCUSSION OF THE PRIOR ART ln known arrangements of this type, airflow rate gauges are provided which regulate the fuel quantity either directly, or through the intermediary of a servomotor, in dependence upon the airflow rate. An arrangement of that type is disclosed and described in German Pat. No. 1,191,177.

During the idling and low load operation of the internal combustion engine, the controlling force provided for by the airflow rate gauge is inadequate to satisfactorily actuate the fuel quantity control arrangement of the control valve of a servomotor.

SUMMARY OF THE INVENTION Accordingly, it is an object of the invention to, in a simple manner, facilitate an undisturbed fuel quantity control from an idling mode through full load operation of the internal combustion engine.

In accordance with the invention, the foregoing object is attained in that the actuation of the fuel quantity control arrangement is carried out through the intermediary of a differential pressure producer which measures the airflow rate, and which includes connected thereto a pneumatic control power amplifier.

In order that the differential pressure at small and large airflow rate does not assume too small or too large a magnitude, it is further proposed that the differential pressure producer be provided with a variable cross-section restriction located in the air intake passageway.

Suitably, the differential pressure producer consists of a baffle valve which is eccentrically positioned in the air intake passageway upstream of the throttle valve, and is mounted on a shaft and mechanically connected with the control power amplifier.

Preferably, the control power amplifier consists of a spring-loaded control pressure piston which is located within a control cylinder, and which is subjected to the prevailing pressure in the air intake passageway upstream and downstream of the differential pressure producer.

In order to simplify the construction, the differential pressure producer and the control power amplifier are provided with a common return or resetting installation, and particularly, a return spring.

In a particular embodiment of the invention, a shaft is located in the rotational axis of the differential pressure producer, by means of which the rotational movement of the latter is transmissible to the fuel quantity control arrangement, and wherein a toothed gear segment is fastened onto the shaft and adapted to cooperatively engage a gear rack which is connected with the control pressure piston of the control power amplifier.

In particular for internal combustion engines having a plurality of operating cylinders, the measured values of the differential pressure producer and any of the particular settings of the throttle valve, or a measured value of the engine rotational speed is suitably converted by means of a rotatable and axially displaceable three-dimensional cam into an integrated signal, and through which there'is controlled a fuel quantity distributor. In that manner, there are advantageously transmitted the measured values of the differential pressure producer through rotation, and the particular position of the throttle valve or the values dependent upon engine speed through axial displacement of the three-dimensional cam, to the fuel quantity distributor the latter of which is provided with a sensing roller. The surface of the cam is profiled in accordance with the characteristic data of the engine.

In order to avoid undesired control disturbances which may occur in response to vibrations of the internal combustion engine and which are caused, for example, during the driving of a vehicle, in accordance with a further aspect of the invention, the differential pressure producer and control power amplifier are so oriented whereby the directions of movement of their movable parts are not directed in a parallel relationship.

Finally, it is also suitable that the quantity of the injected fuel be dependent upon the engine temperature. For this purpose there is, for example, located between the fuel quantity distributor and the injector valve, a differential pressure valve which includes a control membrane, and with the latter being subjected to a control pressure which is received from a control conduit through the intermediary of a temperature-sensitive control pressure valve from a constant pressuremaintained portion of the fuel supply conduit upstream of the fuel quantity distributor.

The fuel injection valve itself is in conformance with the usual type of construction, with or without addition of air.

The advantages which are achieved through the invention consist also in particular that, upon a sudden opening of the throttle valve (acceleration cycle), the differential pressure producer, as well as the control power amplifier, will immediately act more strongly in an opening sense on the fuel quantity control installation due to the sudden increase in differential pressure as would be the actual airflow rate. Herein, additional fuel is released for the acceleration cycle, without the need for any special accelerating pump. Subsequently, the differential pressure producer and control power amplifier return into the position corresponding to the increased airflow rate, which is determined by the spring constants of the return spring.

Upon a sudden throttling of the air inlet, the differential pressure producer, as well as the control power amplifier, advantageously act in a considerably stronger closing sense on the fuelquantity control arrangement, as with the actual reduced airflow rate. This causes the occurrence of a desired leaning, by means of which there are avoided all of the undesirable side effects of an excessively enriched mixture, as for example, unnecessary air pollution due to insufficient combustion. Subsequently, the differential pressure producer and control power amplifier in this case also move again into the position corresponding to the reduced airflow rate.

BRIEF DESCRIPTION OF THE DRAWINGS Reference may now be had to a detailed description of preferred embodiments of the invention, taken m 3 conjunction with the accompanying drawings; in which:

FIG. 1 illustrates an air intake passageway of an internal combustion engine including a fuel control arrangement according to the present invention;

FIG. 2 illustrates the fuel control circuit in further detail;

FIG. 3 shows the detail of the three-dimensional cam of the fuel control arrangement; and

FIG. 4 shows an enlarged sectional detail view of the valve structure for the fuel control arrangement.

DETAILED DESCRIPTION FIG. 1 illustrates an air intake passageway 11 of an internal combustion engine (not shown) through which aspirated air flows in the direction indicated by the arrow. By means of the variably adjustable throttle valve 12 there is regulated the quantity of the throughflowing air. Upstream of the throttle valve 12, the latter of which may be replaced by any other suitably constructed throttle element, there is provided a differential pressure producer 13, which consists of a baffle valve 15 mounted on a shaft 14 eccentrically located in the air intake passageway 11.

The differential pressure producer 13, by means of a toothed gear segment 16 fastened on shaft 14 and through the gear rack 19 connected to the control pressure piston 17 of the control power amplifier 18, is mechanically connected in form fitting relationship with the control power amplifier. The control power amplifier 18 consists of a control cylinder 20, the control pressure piston 17, a return spring 21, a piston rod 22, the gear rack 19 which is fastened to the piston rod, and control pressure conduits 23 and 24.

The control pressure conduit 23 terminates upstream of the baffle valve 15, and the control pressure conduit 24 terminates downstream thereof. The air intake passageway 11 which, in the region of the baffle valve 15, is formed into a rectangular cross-section, is provided with a recess downstream of the baffle valve 15 which is illustrated in the closed operative position, adapted to receive a profile in conformance with the characteristics of the internal combustion engine.

Toothed gear segment 16 and gear rack 19, as shown, are preferably located exteriorly of the air intake passageway 11.

In accordance with FIG. 2, a three-dimensional profile cam 25 is mounted on shaft 14 which is axially displaceable, but is not rotatable relative to the shaft due to a not illustrated groove-spring arrangement. A lever 27 which is pivotable about rotational axis 26 extends with one end thereof into a circumferential groove 28 in the sectionally illustrated cam 25, while the other lever end is rigidly connected with the shaft 30 of the throttle valve lever 31 of throttle valve 12, through the linkably connected rod 29. In this manner, oscillation of the throttle valve 12 leads to a longitudinal displacement, and pivoting of the baffle valve 15 to a central rotation of the three-dimensional cam 25.

The fuel quantity control arrangement 32 consists of a quantity distributing housing 33 having distributing bores 34, 35, 36, 37 which lead through a fuel conduit 40, a differential pressure valve 41, a fuel conduit 42, and an injector valve 43 of standard construction to the suction conduit section above the inlet valves of the four engine cylinders which are illustrated in this example.

Within the fuel quantity distributing housing 33, the quantity distributor 38 is rotatably supported. The latter includes a central bore 39 through which the fuel is introduced, and four radial bores which lead to the distributing bores of the quantity distributing housing 33.

The quantity distributor 38 is rotatable through the intermediary of a lever 44. At the end of the lever 44 there is located a sensing roller 45 which lies on the profiled surface of the cam 25. In accordance with the position of the cam 25, the distributing bores of the quantity distributing housing are more or less offset with respect to the radial bores of the quantity distributors.

The fuel inlet to the quantity distributor is effected through the fuel pump 46 from the fuel receptacle 47 through the fuel conduit 48, the fuel filter 49, the pressure resistance or return valve 61, and the fuel conduits 50 and 51.

A return conduit 53 branches off from the conduit connection 52 for the fuel conduits 50 and 51, and is again connected with the fuel receptacle 47 through a pressure control valve 54, conduit 55, a valve 56, and a conduit 57. The pressure control valve 54 is so adjusted, so that a constant pressure is maintained in the fuel conduit 51 upstream of the quantity distributor 38 with respect to atmosphere.

A further return conduit 58 branches off from conduit connection 52, and which is also connected with the fuel receptacle 47 through a control pressure valve 59, and a conduit 60 with the conduit 55, and from there through the valve and the conduit 57.

A control conduit 62 leads from the control pressure valve 59 to the control pressure chamber of the differential pressure valve 41. The pressure drop of the fuel flowing back through the return conduit 58 and the conduit through the control pressure valve 59 is of significance with respect to the magnitude of the pressure which is present in the control conduit 62.

In FIG. 4 of the drawings, there is illustrated in section a compact construction for a pressure differential valve 41, a return pressure valve 61, control pressure valve 59, control pressure valve 54, and valve 56, together with all associated conduit connections.

The valve construction is built into a housing including an upper portion 63 and a lower portion 64, which are screwed together. In the breach plane between the portions, as far as applicable, there are located the membranes for the valves.

In accordance with FIG. 4, the fuel flows from the fuel receptacle 47 through the fuel conduit 48, the fuel filter 49, and the fuel pump 46, into the inlet connections 65 of the return pressure valve 61. The return pressure valve 61 essentially consists of control membrane 66 having valve plate 67 fastened thereto, the valve seat 68, the valve spring 69, and the actuator 70.

At too low a fuel pressure, for example, when the fuel pump is inactive, the return pressure valve 61, as shown, is closed. Consequently, the fuel cannot flow back into the fuel receptacle 47. At a running fuel pump, the return pressure valve 61 is, however, opened and the fuel flows through the fuel conduit 50. From there a connection to the pressure regulating valve 54 is formed through the return conduit 53.

The pressure regulating valve 54 consists essentially of a cylinder bore 71, a piston 72 adapted to slide therein, a piston spring 73, and an adjusting screw 74 which includes a vent opening 75 to atmosphere. The

piston spring 73 is pretensioned by means of the adjusting screw 74 so that, upon achieving a desired system pressure, the outlet of conduit 55 is released or opened i valve plate 77 which a thereto fastened guide rod 78,

valve spring 79 and closure cap 80. The valve 56 which is closed in the resting position, is opened by means of actuator 70 as soon as the return pressure valve 61 opens. This will release a limited, adjustable opening cross-section. During the resting or inoperative position of the fuel pump 46, the closed valve 56 prevents return flow of the fuel through the conduit 57.

From the fuel conduit 50, in which a constant fuel pressure is continually maintained, there is provided a connection, shown in FIG. 2, to the fuel quantity distributor 38, through the aperture 81 and the (not shown) fuel conduit 51.

A further return conduit 58 leads to the control pressure valve 59, the latter of which essentially consists of a control member 81, a thereto fastened valve plate 82, a valve seat 83, an upper valve spring 84, a lower valve spring 85, and through an expanding material element 86, an adjustable plate spring 87.

From the pressure chamber 88 a bypass conduit 89, which is calibrated through a nozzle 90, leads to the control pressure chamber 91 which is located above the control membrane 81. The throttling provided by the nozzle 90 effects an additional engine start fuel enrichment. A bypass bore 92 located in valve seat 83 further facilitates provision of a definite minimum quantity during operation the return flow.

The elastic material element 86 is dependent upon engine temperature. At a low engine temperature, the plate spring 87 is consequently pulled downwardly so as to reduce the load on the lower membrane spring 85. This has the result that a larger opening cross-section is provided at valve seat 83 so that the pressure drops in the control pressure chamber 91. Since by means control conduit 62 there is provided a connection to the control pressure chamber 93 of the differential pressure valve 41, the pressure therein also drops so that the membrane 94 is downwardly deflected, and thereby takes along a dosing needle 95 which is fastened to the membrane which, in turn, forms a larger opening crosssection for the fuel dosage aperture 97 which is located in a valve housing cover 96. Consequently, through the fuel conduit 40, for a cold engine, there may be advantageously conveyed a larger fuel quantity into the fuel conduit 42, and from there into the injector valve 43, than for a warmer engine (cold start fuel enrichment).

in the modified embodiment shown in FIG. 3, this primarily deviates from the embodiment of FIG. 2 with respect to the longitudinal displacement of the cam 25 in that, at the end of the pivotal lever 27 rotating about rotational axis 26, a force acts which depends upon the engine rotational speed.

For this purpose, there is provided an air pump 99 which is driven in dependence upon rotational speed, and which is in the position to provide an air quantity in dependence upon rotational speed, or respectively, to produce a rotational speed dependent operating pressure.

The operating pressure of the pump comes into effect through the conduit 100 in the control pressure chamber 101 of cylinder 102. As soon as the operating pres- -6 sure increases, the piston 103 located in cylinder 102 is downwardly displaced against the force of return spring 104. The piston rod 1 05 v therebypivots, through the intermediary of a linkage rod98, downwardly towards the right end of thelever 27 so that, ina desired manner, the cam is upwardly displaced. y The primary. advantage ofthe invention lies in the ready availability of a sufficiently large control force also in the idle and low-loadoper'ating ranges of the engine without the need for an additional measure of "valve, in conjunction with th e differential pressure valve, provides a simple cold start fuel enrichment, and in which the elimination of any external energy provides for a compact and unhindered construction.

While there has been shown what is considered to be the preferred embodiment of the invention, it will be obvious that modifications may be made which come within the scope of the disclosure of the specification.

What is claimed is:

1. In a fuel injector arrangement for compressive mixture internal combustion engines including a fuel quantity control installation, and an air intake passageway having a variably actuatable throttle valve disposed therein, the improvement comprising a shaft eccentrically located in said air passageway upstream of said throttle valve, differential pressure producing means for actuating said fuel quantity control installation mounted on said shaft and including a baffle valve, said differential pressure producing means being adapted to measure the air flow rate through said passageway, pneumatic control power amplifier means, and means for mechanically connecting said baffle valve and said control power amplifier means.

2. An arrangement as claimed in claim 1, said control power amplifier means including a control cylinder and a control cylinder piston slidably located in said control cylinder, said piston being subjected to the pressure in said air intake passageway upstream and downstream of said differential pressure producing means.

3. An arrangement as claimed in claim 1, including a common spring-actuated return setting means for said differential pressure producing means and said control power amplifier means.

4. An arrangement as claimed in claim 2, said shaft being positioned on the rotational axis of said differential pressure producing means for transmitting rotation of the latter to said fuel quantity control installation; a toothed gear segment being fastened on said shaft; a gear rack being connected to said control cylinder piston, said gear rack operatively engaging said toothed gear segment for forming said mechanical connecting means.

5.- An arrangement as claimed in claim 1, comprising a rotatable and axially displaceable three-dimensional profiled cam for converting the measured values from said differential pressure producing means and any position of said throttle valve into an integrated signal; and a fuel quantity distributor adapted to be controlled by said integrated signal.

6. An arrangement as claimed in claim 5, said fuel quantity distributor including a sensing roller in contact with said profiled cam for transmitting the measured value of said differential pressure producing means in response to rotation of said cam and the particular position of said throttle valve.

7. An arrangement as claimed in claim 1, said differential pressure producing means and said control power amplifier means being oriented relative to each other so that the directions of movement of their respective movable components are in a non-parallel relationship.

8. An arrangement as claimed in claim 1, the quantity of injected fuel being dependent upon the temperature of the internal combustion engine.

9. An arrangement as claimed in claim 1, comprising a fuel injector valve; a differential pressure valve being connected intermediate said fuel injector valve and said fuel quantity distributor, said differential pressure valve including a control membrane subjected to a of said cam. 

1. In a fuel injector arrangement for compressive mixture internal combustion engines including a fuel quantity control installation, and an air intake passageway having a variably actuatable throttle valve disposed therein, the improvement comprising a shaft eccentrically located in said air passageway upstream of said throttle valve, differential pressure producing means for actuating said fuel quantity control installation mounted on said shaft and including a baffle valve, said differential pressure producing means being adapted to measure the air flow rate through said passageway, pneumatic control power amplifier means, and means for mechanically connecting said baffle valve and said control power amplifier means.
 2. An arrangement as claimed in claim 1, said control power amplifier means including a control cylinder and a control cylinder piston slidably located in said control cylinder, said piston being subjected to the Pressure in said air intake passageway upstream and downstream of said differential pressure producing means.
 3. An arrangement as claimed in claim 1, including a common spring-actuated return setting means for said differential pressure producing means and said control power amplifier means.
 4. An arrangement as claimed in claim 2, said shaft being positioned on the rotational axis of said differential pressure producing means for transmitting rotation of the latter to said fuel quantity control installation; a toothed gear segment being fastened on said shaft; a gear rack being connected to said control cylinder piston, said gear rack operatively engaging said toothed gear segment for forming said mechanical connecting means.
 5. An arrangement as claimed in claim 1, comprising a rotatable and axially displaceable three-dimensional profiled cam for converting the measured values from said differential pressure producing means and any position of said throttle valve into an integrated signal; and a fuel quantity distributor adapted to be controlled by said integrated signal.
 6. An arrangement as claimed in claim 5, said fuel quantity distributor including a sensing roller in contact with said profiled cam for transmitting the measured value of said differential pressure producing means in response to rotation of said cam and the particular position of said throttle valve.
 7. An arrangement as claimed in claim 1, said differential pressure producing means and said control power amplifier means being oriented relative to each other so that the directions of movement of their respective movable components are in a non-parallel relationship.
 8. An arrangement as claimed in claim 1, the quantity of injected fuel being dependent upon the temperature of the internal combustion engine.
 9. An arrangement as claimed in claim 1, comprising a fuel injector valve; a differential pressure valve being connected intermediate said fuel injector valve and said fuel quantity distributor, said differential pressure valve including a control membrane subjected to a control pressure, said control pressure being transmitted from a constant-pressure fuel supply conduit upstream of said fuel quantity distributor, and through a control conduit having a temperature-sensitive control pressure valve.
 10. An arrangement as claimed in claim 5, wherein said profiled cam is adapted to convert the measured values into said integrated signal depending upon engine rotational speed.
 11. An arrangement as claimed in claim 6, wherein the measured value dependent upon engine rotational speed is transmitted in response to axial displacement of said cam. 